1. Field of the Invention
The present invention relates to a fuel system for a vehicle with an engine, particularly to a fuel system which has a canister for adsorbing a fuel vapor (evaporated gas) generated in a fuel tank, and discharges the fuel vapor adsorbed to the canister to an air-intake path leading to the engine.
2. Description of the Related Art
In order to comply with regulations for fuel vapor emission, there has been known a fuel system which has a canister for adsorbing a fuel vapor from a fuel tank and discharges the fuel vapor adsorbed to the canister to an air-intake path leading to the engine, as disclosed in Japanese patent application JP2008-144607A (see paragraphs 0038 and 0039 and FIG. 3) and Japanese patent application JPS-332207A (see paragraphs 0016 to 0018 and FIG. 2). In the vehicles to which such a fuel system is applied, the fuel vapor whose emission amount is set in accordance with operational conditions of the engine is sent to the engine air-intake path, and then appropriately combusted in the engine. These days, such a fuel system is beginning to be applied to utility vehicles, agricultural vehicles, industrial vehicles and the like.
In such a conventional fuel system, only a single pipe is present that connects the fuel tank and the canister. For this reason, when the vehicle runs or stops on a slope and is inclined relative to a horizontal plane, and in turn the fuel tank is inclined, as shown in FIG. 13 of the present application illustrating the prior art, the pipe may be blocked by a fuel in a form of liquid (hereinafter referred to as “liquid fuel”) LF. In this situation, when evaporation of the liquid fuel LF in the fuel tank 2 advances due to raise in an ambient temperature or the like, the fuel vapor (fuel in a gas state) EG generated in the fuel tank 2 cannot escape from the fuel tank 2, leading to increase in an inner pressure of the fuel tank 2. As a result, the liquid fuel LF may reach the canister 3 along the pipe and the canister 3 may disadvantageously be soaked with the liquid fuel LF. The canister 3 soaked with the liquid fuel LF in this manner cannot adsorb the fuel vapor EG.